This K-23 proposal describes a multidisciplinary, cross-cutting career development program, which will enable the Principal Investigator, a Cardiothoracic and Abdominal Radiologist, and an Electrical Engineer, to become a productive independent translational researcher in cardiovascular imaging. The objective of the proposed research is to merge the unique capabilities of computed tomography (CT) and real-time ultrasound (US) to provide a gating signal in order to obtain motion-free CT images of coronary arteries. The PI hypothesizes that US, which provides real-time data similar to electrocardiography (ECG), can directly evaluate cardiac mechanical motion and would be more reliable than ECG at determining relative cardiac akinesia within a cardiac cycle. Coronary artery disease is a significant national healthcare issue, and the evaluation of coronary artery disease is currently based on either (1) catheter coronary angiography (CCA), which is very expensive and invasive with known significant complications or (2) CT coronary angiography (CTCA), which, in its current forms, is either radiation-intensive or unreliable due to motion artifacts. In Aim 1, the PI will evaluate US-gating relative to ECG-gating in determining relative cardiac quiescence. In Aim 2, the PI will evaluate the efficacy of US-derived gating parameters relative to ECG-gating in generating motion-free CTCA from retrospectively-gated CT scans. For Aim 3, the PI will initiate the design and simulation of prototype hardware based on Digital Signal Processing and Field Programmable Gate Array technologies to provide an optimal, prospective real-time trigger for CTCA. The rationale for building hardware is that the stringent temporal resolution requirements for prospective triggering of cardiac CT dictate that the US analysis be performed in real-time on a large volume of data; this cannot be accomplished by software in real-time. The proposed method of gating based on mechanical signals is a paradigm-shift for CTCA and could result in an economical, low-radiation, rapid, non-invasive and reliable technique for evaluating coronary arteries. The most important implication of this development will be a reduction in the number of diagnostic, invasive CCAs that reveal normal arteries, and their associated complications, resulting in dramatic healthcare cost savings. More broadly, the potential impact of this US-based gating technique is that it can be applied directly to other diagnostic problems including respiratory gating for positron-emission tomography-CT and radiation therapy. The proposed K23 scholarship takes advantage of the PI's background combining engineering and medicine and the carefully selected, diverse mentorship/advisory committee which is comprised of world- renowned scientists, and physician-scientists. The career development program has three major components: a technical component, a translational component and a clinical component. The technical component involves the development of a hardware-based triggering technique which will be performed under the mentorship of a leading scientist in biomedical imaging and an engineering professor with extensive academic and industrial experience. Additional focused didactic instruction in image/signal processing and hardware design will be obtained from the Electrical and Computer Engineering and the Biomedical Engineering Departments of the Georgia Institute of Technology. The translational component involves a didactic component, provided by Emory University's Master of Science in Clinical Research program and an Imaging Clinical Trials workshop offered by the Radiological Society of North America. Finally, a clinical research component that involves gathering and analyzing US, ECG and CT data will be performed under the mentorship of internationally recognized pioneers in cardiovascular imaging from the Departments of Radiology and Cardiology at Emory University. The program would take place in an environment which is at the cutting edge of medical imaging, cardiology, and biomedical engineering, with extensive clinical, educational and research resources.